1. Field of the Invention
The present invention relates to a charger and, more particularly, to a charger for a motorized tool, such as a motorized drill, screwdriver and the like.
2. Description of the Related Art
A conventional charger for a motorized tool in accordance with the prior art shown in FIG. 4 is connected between a mains supply 1 and a battery 8 and comprises a rectifier circuit 2a connected to the mains supply 1 to convert the alternating current voltage into a direct current voltage which functions as an input voltage, a pulse width modulation (PWN) circuit 3a connected to the rectifier circuit 2a to control a pulse width by the input voltage from the rectifier circuit 2a, and a transformer circuit 4a connected to the PWN circuit 3a and including a primary winding so that the input voltage is supplied to the primary winding of the transformer circuit 4a to gradually increase and store an energy in the primary winding of the transformer circuit 4a to produce an output voltage for charging the battery 8. However, the charging process is easily interrupted by impurities, thereby decreasing the voltage, elongating the charging time, and causing loss of the power. In addition, the charger is only used to charge the battery of a determined specification, thereby limiting the versatility of the charger.